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MacOS(Apple Silicon) IOKit driver for FPGA DMA transmission, kernel panic.
MacOS(Apple Silicon) IOKit driver for FPGA DMA transmission, kernel panic. Hardware and software configuration: MAC mini M1 2020 16GB, macOS Ventura 13.0 or 13.7.8 FPGA device capability: 64-bit Complete description: We've developed a DMA driver for PCIe devices (FPGA) based on IOKit. The driver can start normally through kextload, and the bar mapping, DMA registers, etc. are all correct. I am testing DMA data transmission, but a kernel panic has occurred. The specific content of the panic is as follows: {"bug_type":"210","timestamp":"2026-01-28 14:35:30.00 +0800","os_version":"macOS 13.0 (22A380)","roots_installed":0,"incident_id":"61C9B820-8D1B-4E75-A4EB-10DC2558FA75"} { "build" : "macOS 13.0 (22A380)", "product" : "Macmini9,1", "socId" : "0x00008103", "kernel" : "Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103", "incident" : "61C9B820-8D1B-4E75-A4EB-10DC2558FA75", "crashReporterKey" : "6435F6BD-4138-412A-5142-83DD7E5B4F61", "date" : "2026-01-28 14:35:30.16 +0800", "panicString" : "panic(cpu 0 caller 0xfffffe0026c78c2c): "apciec[pcic0-bridge]::handleInterrupt: Request address is greater than 32 bits linksts=0x99000001 pcielint=0x02220060 linkcdmsts=0x00000000 (ltssm 0x11=L0)\n" @AppleT8103PCIeCPort.cpp:1301\nDebugger message: panic\nMemory ID: 0x6\nOS release type: User\nOS version: 22A380\nKernel version: Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103\nFileset Kernelcache UUID: C222B4132B9708E5E0E2E8B8C5896410\nKernel UUID: 0BFE6A5D-118B-3889-AE2B-D34A0117A062\nBoot session UUID: 61C9B820-8D1B-4E75-A4EB-10DC2558FA75\niBoot version: iBoot-8419.41.10\nsecure boot?: YES\nroots installed: 0\nPaniclog version: 14\nKernelCache slide: 0x000000001d1b4000\nKernelCache base: 0xfffffe00241b8000\nKernel slide: 0x000000001e3f8000\nKernel text base: 0xfffffe00253fc000\nKernel text exec slide: 0x000000001e4e0000\nKernel text exec base: 0xfffffe00254e4000\nmach_absolute_time: 0x907c3082\nEpoch Time: sec usec\n Boot : 0x6979adbb 0x00023a6a\n Sleep : 0x00000000 0x00000000\n Wake : 0x00000000 0x00000000\n Calendar: 0x6979ae1a 0x00064953\n\nZone info:\n Zone map: 0xfffffe1000834000 - 0xfffffe3000834000\n . VM : 0xfffffe1000834000 - 0xfffffe14cd500000\n . RO : 0xfffffe14cd500000 - 0xfffffe1666e98000\n . GEN0 : 0xfffffe1666e98000 - 0xfffffe1b33b64000\n . GEN1 : 0xfffffe1b33b64000 - 0xfffffe2000830000\n . GEN2 : 0xfffffe2000830000 - 0xfffffe24cd4fc000\n . GEN3 : 0xfffffe24cd4fc000 - 0xfffffe299a1c8000\n . DATA : 0xfffffe299a1c8000 - 0xfffffe3000834000\n Metadata: 0xfffffe3f4d1ac000 - 0xfffffe3f551ac000\n Bitmaps : 0xfffffe3f551ac000 - 0xfffffe3f5ac94000\n\nCORE 0 recently retired instr at 0xfffffe002569d7a0\nCORE 1 recently retired instr at 0xfffffe002569eea0\nCORE 2 recently retired instr at 0xfffffe002569eea0\nCORE 3 recently retired instr at 0xfffffe002569eea0\nCORE 4 recently retired instr at 0xfffffe002569eea0\nCORE 5 recently retired instr at 0xfffffe002569eea0\nCORE 6 recently retired instr at 0xfffffe002569eea0\nCORE 7 recently retired instr at 0xfffffe002569eea0\nTPIDRx_ELy = {1: 0xfffffe2000c23010 0: 0x0000000000000000 0ro: 0x0000000000000000 }\nCORE 0 PVH locks held: None\nCORE 1 PVH locks held: None\nCORE 2 PVH locks held: None\nCORE 3 PVH locks held: None\nCORE 4 PVH locks held: None\nCORE 5 PVH locks held: None\nCORE 6 PVH locks held: None\nCORE 7 PVH locks held: None\nCORE 0 is the one that panicked. Check the full backtrace for details.\nCORE 1: PC=0xfffffe00279db94c, LR=0xfffffe00260d5d9c, FP=0xfffffe8ffecaf850\nCORE 2: PC=0xfffffe0025be76b0, LR=0xfffffe0025be7628, FP=0xfffffe8fff08f5f0\nCORE 3: PC=0x00000001c7cacd78, LR=0x00000001c7cacd84, FP=0x000000016f485130\nCORE 4: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffe1dff00\nCORE 5: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff5eff00\nCORE 6: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffed8bf00\nCORE 7: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff11bf00\nCompressor Info: 0% of compressed pages limit (OK) and 0% of segments limit (OK) with 0 swapfiles and OK swap space\nPanicked task 0xfffffe1b33aad678: 0 pages, 470 threads: pid 0: kernel_task\nPanicked thread: 0xfffffe2000c23010, backtrace: 0xfffffe8fff6eb6a0, tid: 265\n\t\t ... Kernel Extensions in backtrace:\n com.apple.driver.AppleT8103PCIeC(1.0)[A595D104-026A-39E5-93AA-4C87CE8C14D2]@0xfffffe0026c619d0->0xfffffe0026c86c97\n dependency: com.apple.driver.AppleARMPlatform(1.0.2)[11A9713E-6739-3A4C-8571-2D8EAA062278]@0xfffffe0025f13ff0->0xfffffe0025f6255f\n dependency: com.apple.driver.AppleEmbeddedPCIE(1)[E71CBCCD-AEB8-3E7B-933D-4FED4241BF13]@0xfffffe002654e0b0->0xfffffe00265684c7\n dependency: com.apple.driver.ApplePIODMA(1)[A419BABC-A7A3-316D-A150-7C2C2D1F6D53]@0xfffffe00269a24b0->0xfffffe00269a6c3b\n dependency: com.apple.driver.IODARTFamily(1)[03997E20-8A3F-3412-A4E8-BD968A75A07D]@0xfffffe00275bcf50->0xfffffe00275d0a3f\n dependency: com.apple.iokit.IOPCIFamily(2.9)[EC78F47B-530B-3F87-854E-0A0A5FD9BBB2]@0xfffffe0027934350->0xfffffe002795f3d3\n dependency: com.apple.iokit.IOReportFamily(47)[843B39D3-146E-3992-B7C7-960148685DC8]@0xfffffe0027963010->0xfffffe0027965ffb\n dependency: com.apple.iokit.IOThunderboltFamily(9.3.3)[B22BC005-BB7B-32A3-99C0-39F3BDBD8E54]@0xfffffe0027a5e3f0->0xfffffe0027b9a1a3\n\nlast started kext at 1915345919: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nlast stopped kext at 1774866338: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nloaded It seems that the DMA request address initiated by FPGA exceeded 32 bits, which was intercepted by PCIe root port and resulted in a kernel panic.This is also the case on macOS (M2). I have tried the following code interface: IOBufferMemoryDescriptor: a. withCapacity(bufferSize, kIODirectionInOut, true); b. inTaskWithPhysicalMask(kernel_task, kIODirectionInOut, bufferSize, 0x00000000FFFFFFFFULL)。 The physical addresses of the constructed descriptors are all >32 bits; IODMACommand: a. withSpecification(kIODMACommandOutputHost64, 64, 0, IODMACommand::kMapped, 0, 0),gen64IOVMSegments() The allocated IOVM address must be>32 bits, which will generate a kernel panic when used later. b.withSpecification(kIODMACommandOutputHost32, 32, 0, IODMACommand::kMapped, 0, 0),gen32IOVMSegments() The allocation of IOVM failed with error code kIOReturnenMessageTooLarge. So after the above attempts, the analysis shows that the strategy of Dart+PCIe root port on macOS (Apple Silicon) is causing the failure of 64 bit DMA address transfer. I have two questions: a. Does Dart in macOS (Apple Silicon) definitely not allocate <=32-bit IOVM addresses? b. Is there any other way to achieve DMA transfer for FGPA devices on macOS (Apple Silicon)? Thanks!
9
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624
Feb ’26
Missing "Dolby Vision Profile" Option in Deliver Page - DaVinci Resolve 20 on iPadOS 26
Dear Support Team, ​I am writing to seek technical assistance regarding a persistent issue with Dolby Vision exporting in DaVinci Resolve 20 on my iPad Pro 12.9-inch (2021, M1 chip) running iPadOS 26.0.1. ​The Issue: Despite correctly configuring the project for a Dolby Vision workflow and successfully completing the dynamic metadata analysis, the "Dolby Vision Profile" dropdown menu (and related embedding options) is completely missing from the Advanced Settings in the Deliver page. ​My Current Configuration & Steps Taken: ​Software Version: DaVinci Resolve Studio 20 (Studio features like Dolby Vision analysis are active and functional). ​Project Settings: Color Science: DaVinci YRGB Color Managed. ​Dolby Vision: Enabled (Version 4.0) with Mastering Display set to 1000 nits. ​Output Color Space: Rec.2100 ST2084. ​Color Page: Dynamic metadata analysis has been performed, and "Trim" controls are functional. ​Export Settings: ​Format: QuickTime / MP4. ​Codec: H.265 (HEVC). ​Encoding Profile: Main 10. ​The Problem: Under "Advanced Settings," there is no option to select a Dolby Vision Profile (e.g., Profile 8.4) or to "Embed Dolby Vision Metadata." ​Potential Variables: ​System Version: I am currently running iPadOS 26. ​Apple ID: My iPad is currently not logged into an Apple ID. I suspect this might be preventing the app from accessing certain system-level AVFoundation frameworks or Dolby DRM/licensing certificates required for metadata embedding. ​Could you please clarify if the "Dolby Vision Profile" option is dependent on a signed-in Apple ID for hardware-level encoding authorization, or if this is a known compatibility issue with the current iPadOS 26 build? ​I look forward to your guidance on how to resolve this. ​Best regards, INSOFT_Fred
0
0
220
Feb ’26
iOS printing – Finishing (Punch) options not applied for images unless a preset is selected
When printing image/photo files via AirPrint, selected finishing options (e.g., Punch) are not applied unless a preset is chosen. reproduction steps: Select an image on iOS Tap Print → choose printer/server Set Finishing Options → Punch Print Observed: Finishing options not applied IPP trace shows no finisher attributes in the request working scenario: Select any Preset (e.g., Color) before printing Finishing options are then included in IPP and applied Note: Issue does not occur when printing PDFs from iOS; finisher attributes are sent correctly. Is this expected AirPrint behavior for image jobs, or could this be a bug in how iOS constructs the IPP request for photos?
3
0
261
Mar ’26
macOS 26.4 Beta breaks keyboard remapping for built-in MacBook keyboards – significant ecosystem impact
Since macOS 26.4 Beta 1, virtual HID devices created via DriverKit can no longer intercept key events from the built-in MacBook keyboard. External keyboards still work. This is confirmed and tracked here: https://github.com/pqrs-org/Karabiner-Elements/issues/4402 One possible lead (from LLM-assisted analysis of Apple's open-source IOHIDFamily code and cross-referencing community reports): macOS 26.4 Beta may have introduced or modified a security policy referred to as com.apple.iohid.protectedDeviceAccess, which could block IOHIDDeviceOpen for the Apple Internal Keyboard connected via SPI transport (AppleHIDTransportHIDDevice). This appears related to a "GamePolicy" check in IOHIDDeviceClass.m that gates whether processes can open HID devices. This has not been independently verified and may or may not be the root cause. This has far-reaching consequences. Karabiner-Elements alone has over 21,000 GitHub stars and is used by hundreds of thousands of macOS users for keyboard customization, accessibility workflows, ergonomic setups, and multilingual input. This change completely breaks its core functionality on any MacBook. Beyond Karabiner, this affects every developer building keyboard remapping, input customization, or accessibility tooling via DriverKit virtual HID devices — including commercial applications currently in development. I'd argue that the power and flexibility of keyboard customization on macOS is a genuine competitive advantage for the platform. Developers and power users choose Macs partly because tools like this exist. Restricting this capability would be detrimental to the ecosystem and to Apple's appeal among professional users. I'd like to understand: is this an intentional security change or a regression? If intentional, is there a migration path?
1
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221
Mar ’26
Can't get USBSerialDriverKit driver loaded
I am writing a DriverKit driver for the first that uses the USBSerialDriverKit. The driver its purpose is to expose the device as serial interface (/dev/cu.tetra-pei0 or something like this). My problem: I don't see any logs from that driver in the console and I tried like 40 different approaches and checked everything. The last message I see is that the driver get successfully added to the system it is in the list of active and enabled system driver extensions but when I plug the device in none of my logs appear and it doesn't show up in ioreg. So without my driver the target device looks like this: +-o TETRA PEI interface@02120000 <class IOUSBHostDevice, id 0x10000297d, registered, matched, active, busy 0 (13 ms), retain 30> | { | "sessionID" = 268696051410 | "USBSpeed" = 3 | "UsbLinkSpeed" = 480000000 | "idProduct" = 36886 | "iManufacturer" = 1 | "bDeviceClass" = 0 | "IOPowerManagement" = {"PowerOverrideOn"=Yes,"DevicePowerState"=2,"CurrentPowerState"=2,"CapabilityFlags"=32768,"MaxPowerState"=2,"DriverPowerState"=0} | "bcdDevice" = 9238 | "bMaxPacketSize0" = 64 | "iProduct" = 2 | "iSerialNumber" = 0 | "bNumConfigurations" = 1 | "UsbDeviceSignature" = <ad0c16901624000000ff0000> | "USB Product Name" = "TETRA PEI interface" | "locationID" = 34734080 | "bDeviceSubClass" = 0 | "bcdUSB" = 512 | "USB Address" = 6 | "kUSBCurrentConfiguration" = 1 | "IOCFPlugInTypes" = {"9dc7b780-9ec0-11d4-a54f-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | "UsbPowerSinkAllocation" = 500 | "bDeviceProtocol" = 0 | "USBPortType" = 0 | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | "USB Vendor Name" = "Motorola Solutions, Inc." | "Device Speed" = 2 | "idVendor" = 3245 | "kUSBProductString" = "TETRA PEI interface" | "kUSBAddress" = 6 | "kUSBVendorString" = "Motorola Solutions, Inc." | } | +-o AppleUSBHostCompositeDevice <class AppleUSBHostCompositeDevice, id 0x100002982, !registered, !matched, active, busy 0, retain 5> | { | "IOProbeScore" = 50000 | "CFBundleIdentifier" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "IOProviderClass" = "IOUSBHostDevice" | "IOClass" = "AppleUSBHostCompositeDevice" | "IOPersonalityPublisher" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "bDeviceSubClass" = 0 | "CFBundleIdentifierKernel" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "IOMatchedAtBoot" = Yes | "IOMatchCategory" = "IODefaultMatchCategory" | "IOPrimaryDriverTerminateOptions" = Yes | "bDeviceClass" = 0 | } | +-o lghub_agent <class AppleUSBHostDeviceUserClient, id 0x100002983, !registered, !matched, active, busy 0, retain 7> | { | "IOUserClientCreator" = "pid 1438, lghub_agent" | "IOUserClientDefaultLocking" = Yes | } | +-o IOUSBHostInterface@0 <class IOUSBHostInterface, id 0x100002986, registered, matched, active, busy 0 (5 ms), retain 9> | | { | | "USBPortType" = 0 | | "IOCFPlugInTypes" = {"2d9786c6-9ef3-11d4-ad51-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | | "USB Vendor Name" = "Motorola Solutions, Inc." | | "bcdDevice" = 9238 | | "USBSpeed" = 3 | | "idProduct" = 36886 | | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | | "bInterfaceSubClass" = 0 | | "bConfigurationValue" = 1 | | "locationID" = 34734080 | | "USB Product Name" = "TETRA PEI interface" | | "bInterfaceProtocol" = 0 | | "iInterface" = 0 | | "bAlternateSetting" = 0 | | "idVendor" = 3245 | | "bInterfaceNumber" = 0 | | "bInterfaceClass" = 255 | | "bNumEndpoints" = 2 | | } | | | +-o lghub_agent <class AppleUSBHostInterfaceUserClient, id 0x100002988, !registered, !matched, active, busy 0, retain 6> | { | "UsbUserClientBufferStatistics" = {"IOMemoryDescriptor"=0,"IOBufferMemoryDescriptor"=0,"IOSubMemoryDescriptor"=0} | "IOUserClientCreator" = "pid 1438, lghub_agent" | "UsbUserClientBufferAllocations" = {"Bytes"=0,"Descriptors"=0} | "IOUserClientDefaultLocking" = Yes | } | +-o IOUSBHostInterface@1 <class IOUSBHostInterface, id 0x100002987, registered, matched, active, busy 0 (5 ms), retain 9> | { | "USBPortType" = 0 | "IOCFPlugInTypes" = {"2d9786c6-9ef3-11d4-ad51-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | "USB Vendor Name" = "Motorola Solutions, Inc." | "bcdDevice" = 9238 | "USBSpeed" = 3 | "idProduct" = 36886 | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | "bInterfaceSubClass" = 0 | "bConfigurationValue" = 1 | "locationID" = 34734080 | "USB Product Name" = "TETRA PEI interface" | "bInterfaceProtocol" = 0 | "iInterface" = 0 | "bAlternateSetting" = 0 | "idVendor" = 3245 | "bInterfaceNumber" = 1 | "bInterfaceClass" = 255 | "bNumEndpoints" = 2 | } | +-o lghub_agent <class AppleUSBHostInterfaceUserClient, id 0x10000298a, !registered, !matched, active, busy 0, retain 6> { "UsbUserClientBufferStatistics" = {"IOMemoryDescriptor"=0,"IOBufferMemoryDescriptor"=0,"IOSubMemoryDescriptor"=0} "IOUserClientCreator" = "pid 1438, lghub_agent" "UsbUserClientBufferAllocations" = {"Bytes"=0,"Descriptors"=0} "IOUserClientDefaultLocking" = Yes } more details in my comment.
6
0
367
Mar ’26
Kernel Panic: Power state transition (0 -> 2) timeout during DriverKit (DEXT) load sequence (IOUserSCSIParallelInterfaceController)
Hi Everyone, We are currently migrating a mature legacy KEXT to DriverKit for our PCIe SCSI storage controller (connected via Thunderbolt 3). During the DEXT load sequence, we have observed that the system automatically triggers a power state transition from State 0 (Off) to State 2 (On). However, this process results in a Kernel Panic due to a timeout after approximately 21 seconds. We have verified that our implementation of Start_Impl, UserInitializeController_Impl, and SetPowerState_Impl executes extremely fast, with a total execution time of less than one second. Specifically, SetPowerState_Impl returns kIOReturnSuccess immediately upon being called. Furthermore, our current Info.plist does not contain any IOPowerManagement dictionary or related keys. Despite the fast execution and the absence of explicit power management declarations in the plist, the kernel power management state machine (IOServicePM) still generates a 21-second timeout, leading to the following panic: Panic Log: panic(cpu 7 caller 0xfffffe0020be8fec): MySCSIDriver::setPowerState(0xfffffe2fb1a65c00 : 0xfffffe0020bfed88, 0 -> 2) timed out after 21257 ms @IOServicePM.cpp:5609 com.example.driver.dext: ( id: com.example.driver.dext; path: /Library/SystemExtensions/[UUID]/com.example.driver.dext; state: loaded ) Note on Previous Discussion: I would like to express my gratitude to Kevin from Apple DTS for the helpful discussion regarding the implementation of BundleParallelTask on the forums. Since then, we have shifted our development focus toward completing the overall management ecosystem, delivering a comprehensive operational interface for users, and handling specific user environments and behaviors. Our current priority is ensuring system stability—specifically resolving these Thunderbolt-related power management issues (sleep/wake)—to prepare the product for upcoming testing. I remain very grateful for the guidance provided on batch task optimization and intend to resume those optimizations once this critical stability baseline is secured. Technical Guidance Needed for PM Migration In our legacy KEXT, we utilized PMinit(), registerPowerDriver(), and joinPMtree() to precisely control the timing of power management registration. In transitioning to the DriverKit SDK, we have not found clear guidance on several key points: Standardized Migration Path: What is the recommended way to implement equivalent power management initialization (formerly PMinit) within a DriverKit subclass? In DriverKit, how should we replicate the behavior of manually calling registerPowerDriver and joinPMtree to ensure the driver is only monitored once the hardware is ready? Implicit Power Registration: Why does the system enforce a setPowerState(0 -> 2) transition on a subclass of IOUserSCSIParallelInterfaceController even when no IOPowerManagement dictionary is defined in the Info.plist? Is this a default behavior of the SCSI or PCI transport framework? Thunderbolt Specifics: Are there specific power proxying requirements or configurations for PCIe devices over Thunderbolt to avoid conflicts with the default IOPCIFamily power policies? Best Regards, Charles
3
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248
Mar ’26
DriverKit Entitlement Model Has No Viable Path for Open Source and Community-Maintained Drivers
While I welcome the arrival of a userspace implementation of drivers, DriverKit as it stands has some notable flaws. My main concern is the ability of open-source projects like HoRNDIS being able to access paid developer accounts and the limited entitlement scope (plus the waiting period) for what is essentially a hobbyist free project. Even if the developer is a professional company, some legacy hardware will go unsupported because of a lack of support from the vendor. Providing a way for users who need access to older hardware would be needed. Three concrete requests: A class-level or wildcard VID/PID entitlement for open source projects with a verifiable public repository A free or reduced-cost entitlement path for non-commercial volunteer-maintained drivers Published approval criteria and timelines so projects can plan accordingly Depreciating kexts without providing an accessible successor for community projects isn't security, it is gatekeeping access to hardware that is critically needed. Is this use case on the roadmap at all? Developers deserve a clear answer.
1
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184
Mar ’26
iOS AirPrint sends print-quality=high when file-type is photo even if user selects “normal”
Hi everyone, I observed a behavior with AirPrint from an iPhone and wanted to confirm if this is expected behavior from iOS. Scenario tested: File type: Photo Print-quality selected by the user: Normal Observation (from packet capture): When checking the PCAP for the request sent from the iPhone, the print-quality attribute is always sent as high, even though the user selected Normal in the UI. Question: Is this an expected behavior in iOS/AirPrint where photos are always sent with print-quality=high regardless of the user-selected print quality? Or could this be a bug?
0
0
145
Mar ’26
Why don't my os_log entries show up until the second time my driver loads?
I'm in the process of writing a DriverKit USBHostInterface driver, and while I'm finally starting to get there, I've run into a bit of a frustration with logging. Naturally I have a liberal amount of os_log calls that I'm using to troubleshoot my driver. However I've noticed that they don't show up until after the first time my driver has loaded. Meaning, for example, suppose I make a new build of my driver and it's bundled user-mode app, install the bundle to /Applications, run the installer, verify it took with systemextensionsctl list, fire up Console and start streaming log entries, then plug in my device. I can see the log entries that show that my driver is loaded, etc., then a bunch of kernel -> log entries, but none of my Start method log entries. If I unplug my device and plug it in again, my log entries show up as expected. Why is this and, more importantly, how can I fix it? I'd like to see those log entries the first time the driver loads, if I could.
3
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204
Mar ’26
Supported way to expose an iPhone+controller as a macOS gamepad without restricted entitlements?
I’m prototyping a personal-use system that lets an iPhone with a physically attached controller act as an input device for a Mac. End goal: Use the iPhone as the transport and sensor host Use the attached physical controller for buttons/sticks Map the iPhone gyroscope to the controller’s right stick to get gyro aim in Mac games / cloud-streamed games such as GeForce NOW that don't support the gyro. What I’m trying to understand is whether Apple supports any path for this on macOS that does NOT require restricted entitlements or paid-program-only capabilities. What I’ve already found: CoreHID virtual HID device creation appears to require com.apple.developer.hid.virtual.device HIDDriverKit / system extensions appear to require Apple-granted entitlements as well GCVirtualController does not seem to solve the problem because I need a controller-visible device that other apps can see, not just controls inside my own app So my concrete question is: Is there any supported, entitlement-free way for a personal macOS app to expose a game-controller-like input device that other apps can consume system-wide? If not, is the official answer that this class of solution necessarily requires one of: CoreHID with restricted entitlement HIDDriverKit/system extension entitlement some other Apple-approved framework or program I’m missing I’m not asking about App Store distribution. This is primarily for local/personal use during development. I’m trying to understand the supported platform boundary before investing further. Any guidance on the recommended architecture for this use case would be appreciated.
3
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215
Mar ’26
Dual Monitor Studio Display XDR fails on MacBook Pro M4 Pro
I have two Macbook Pros: 14" M4 Pro (company) 16" M4 Max (personal) I work remote full-time and recently purchased 2 of the new Studio Display XDRs. Everything works perfectly however I chose to connect them to the M4 Max. I have a caldigit Element TB5 hub and can daisy chain both monitors through that perfectly. With that said, no matter how I plug them into the M4 Pro I can only ever get one to light up at a time. What I have tried to resolve it: Plug them in individually to the m4 pro Plug them in one at a time, force them to 60hz and then plug them both in. Daisy Chaining the displays Daisy Chaining the displays through the TB5 Hub Nothing works. Only one display comes on and its whichever is plugged in first. I have even tried lowering the refresh to as low as it goes on both manually then plugging them back in. Still nothing. From what I am reading it appears to be that the M4 Pro has 3 display lanes and when I plug the first studio display XDR it is using 2 lanes. If I go down to 60hz which is what the original studio display was, then it should theoretically go down to 1 display lane allowing a second to be plugged in. A bunch of people had the older studio display running 2x 5k ASD monitors on the M4 Pro. Now with the latest Studio Display XDR I am stuck. I was researching possibly editing the EDID of each to mimic the older studio display, but I don't know how to do that easily without BetterDisplay and right now I have no ability to install that. There is a chance I can get approval to run commands / BetterDisplay to get this working if a solution can be found. What I think the ultimate fix is for the firmware / macOS to realize the limitation, force the studio display XDR to 60hz when a second monitor is plugged in and they both would work. A single Studio Display XDR could run 120hz, but immediately upon plugging a second one it swaps to 60hz. I am completely fine with that scenario. I have found a few discussions about this topic with the main one being on apple discussions: https://discussions.apple.com/thread/256262701?sortBy=rank&answerId=261888577022 Someone sort of gave me this idea on Mac because they were trying to use the studio display XDR on windows and it appears to have worked with cloning an older ASD EDID on the new model: https://www.reddit.com/r/mac/comments/1s3ani5/got_studio_display_xdr_working_on_windows_pc_5k/ I don't really know what else to do. I opened a ticket with support. Case # 102853480566, but it went no where. I got disconnected during the first call after describing everything and when they reached back out they didn't even give me 2 seconds to pick up and they hung up and closed the ticket. I really don't want to return the displays because they are beautiful and work beautifully on the m4 max. They should work with 60hz on the m4 pro. Who / How / When can we get this resolved? I would be happy to work with an Apple dev / engineer to help resolve this.
1
0
158
Mar ’26
iPhone 16 Pro Max — 180s SpringBoard freeze + reboot, started iOS 26.4 Beta 3, persists on stable 26.4
iPhone16PM Clean DFU, no restore, no tweaks. Started on iOS 26.4.3 and still happening on iOS 26.4. Triggers: ∙ Editing Home Screen widgets ∙ Heavy media in Safari ∙ ProMotion UI transitions Panic log — 0x8badf00d watchdog timeout: userspace watchdog timeout: no successful checkins from SpringBoard in 180 seconds. service: backboardd Drivers: com.apple.driver.AppleAVD + com.apple.iokit.IOSurface Is there a solution for this? Thank you.
2
0
152
Apr ’26
Does using HIDVirtualDevice rule out Mac App Store distribution?
Hi, I’m looking for clarification from folks familiar with CoreHID rather than App Review, as the guys there have not responded to my post (https://developer.apple.com/forums/thread/820676) We have a sandboxed macOS app that creates a virtual HID device (HIDVirtualDevice) as described in Creating virtual devices https://developer.apple.com/documentation/corehid/creatingvirtualdevices To work at all, the app requires the entitlement: com.apple.developer.hid.virtual.device With this entitlement present, macOS shows the system prompt requesting Accessibility permission App would like to control this computer using accessibility features. Grant access to this application in Security and Privacy preferences located in System Preferences. when HIDVirtualDevice(properties:) is called. There is no mention of Accessibility in the HIDVirtualDevice documentation, but the behavior is reproducible and seems unavoidable. My question is therefore: Is creating a virtual HID device from userspace via HIDVirtualDevice considered inherently incompatible with Mac App Store distribution? In other words: Is the Accessibility prompt an expected side‑effect of this API? And if so, does that mean using HIDVirtualDevice is only practical for direct (non–App Store) distribution unless the app is explicitly an accessibility tool? I’m not asking about review policy details—just whether, from a technical/system point of view, HIDVirtualDevice is actually intended to be usable by App Store apps. For context, there seem to be public, non‑accessibility uses of Apple’s virtual HID infrastructure, like this recent post: https://developer.apple.com/forums/thread/820708 and corresponding Github repo this project. I don't know if these intend to use the App Store, but they might end up in the same situation. Any insights from people who’ve worked with CoreHID would be greatly appreciated. Thanks, Magnus
6
0
204
2w
I requested "DirverKit UserClient Access" Entitlement, But I Distribute App failed.
I requested "DirverKit UserClient Access" Entitlement, But I Distribute App failed. I don't know the reason. I think when I request "DirverKit UserClient Access" I make a mistake. I fill in two Bundle ids in the "Request a System Extension or DriverKit Entitlement" form's "UserClient Bundle IDs" item. The reason is when I Add "DirverKit UserClient Access" Capability in the project of Xcode. The .entitlements file is like this: <string>com.turing.TuringTouch com.turing.TuringTouch.TouchDriver</string> But in "Signing" of Xcode's "Bundle Identifier" can fill in only on "Identifier" therefore they do not match. So I can't Distribute App. I reapply "DirverKit UserClient Access" Entitlement. But decline. The result is "decline". Please help me. Please tell me, how should can I do now? Thank you very much.
1
0
142
2w
Driverkit driver hangs on macOS
Hello, I have crated a DriverKit driver for macOS and iPad M-series if I ever get the mac driver working. I have the correct entittlements, and matching provisioning profile downloaded manually. The driver loads (no errors!), and is visible in ioreg below the usb device (when plugged). The issue is that I never get any log from the driver, have reduced to minimal working code (below). When I debug with lldb, I load the symbols for my driver and break on init and Start - but lldb never triggers == never calls start or init. This is also why no logs. When I unplug the device, the driver process (ps aux) keeps running, causes a hard crash of the Mac with dext remove/or kill driver.dext process. I have asked Claude - but its just running in circles: check Info.plist=ok, check entitlements=ok, check code (minimal)=ok, check iig=ok, check provisioning profile=ok, check build settings=ok, check ioreg=ok, check code signature=ok, start over I don't get any log from my driver, which is consistent with init() not being called. All logs from kernel & friends (AMFI) do show the driver loading - no errors. Any tips appreciated! // USBDriver.iig #ifndef USBDriver_h #define USBDriver_h #include <USBDriverKit/IOUSBHostInterface.iig> class USBDriver: public IOService { public: virtual bool init() override; virtual void free() override; virtual kern_return_t Start(IOService * provider) override; virtual kern_return_t Stop(IOService * provider) override; }; // USBDriver.cpp #include <os/log.h> #include <DriverKit/DriverKit.h> #include "USBDriver.h" bool USBDriver::init() { if (!super::init()) return false; os_log(OS_LOG_DEFAULT, "terminal.driver: init()"); return true; } kern_return_t IMPL(USBDriver, Start) { os_log(OS_LOG_DEFAULT, "terminal.driver: Start()"); kern_return_t ret = super::Start(provider); if (ret != kIOReturnSuccess) { os_log(OS_LOG_DEFAULT, "terminal.driver: super::Start failed: 0x%08x", ret); return ret; } os_log(OS_LOG_DEFAULT, "terminal.driver: Start() success"); return super::Start(provider); } kern_return_t IMPL(USBDriver, Stop) { os_log(OS_LOG_DEFAULT, "terminal.driver: Stop()"); return super::Stop(provider); } void USBDriver::free() { os_log(OS_LOG_DEFAULT, "terminal.driver: free()"); super::free(); }
2
0
156
2w
HID Device Access / Mode Switch
I might be trying to achieve the impossible here, but if there's another way to go about it any advice would be appreciated. I've got an older Linux application that reflashes firmware on a connected USB HID device that I'm trying to port to macOS. Essentially the device starts as an HID interface (0x03/0x01/0x01) but to update firmware receives a simple control payload and then restarts and connects as a different (non-HID) device. However I can't open the HID device at all, I'm guessing this is some sort of permission error (SIP?). AppleUSBHostUserClient::openGated: failed to open IOUSBHostDevice... provider is already opened for exclusive access by AppleUSB20Hub hid_open_path: failed to open IOHIDDevice from mach entry: (0xE00002E2) not permitted AppleUSBXHCICommandRing::setAddress: completed with result code 4 AppleUSBHostPort::createDevice: failed to create device (0xe00002bc) AppleUSBIORequest ... transaction error ... 0xe00002ed Is there any way at all to do this on macOS? Interestingly if you run a Windows VM in VMWare or similar and connect the device to that VM it works, so there's obviously some way but I'd like to create a simple standalone tool.
1
0
194
2w
macOS Preview appears to hold MTP devices open indefinitely
I am developing a USB MTP device for use with macOS. When the device is connected while Preview is running, I observe the host send OpenSession, then GetDeviceInfo, and then no further MTP commands. I do not see a later CloseSession. Problem is that once this happens, exclusive access to the USB interface is retained, so another application cannot connect to the device. From the device side, there is no obvious way to recover except forcing a USB disconnect/reset or shutting down the USB interface. My questions are: Is this expected behavior for Preview, or for a Preview-related macOS helper? Is it expected on macOS that a client may open an MTP session and then leave it idle without sending CloseSession? I am mainly trying to understand whether this is expected macOS behavior, or whether this should be considered a bug.
3
0
90
1w
MacOS(Apple Silicon) IOKit driver for FPGA DMA transmission, kernel panic.
MacOS(Apple Silicon) IOKit driver for FPGA DMA transmission, kernel panic. Hardware and software configuration: MAC mini M1 2020 16GB, macOS Ventura 13.0 or 13.7.8 FPGA device capability: 64-bit Complete description: We've developed a DMA driver for PCIe devices (FPGA) based on IOKit. The driver can start normally through kextload, and the bar mapping, DMA registers, etc. are all correct. I am testing DMA data transmission, but a kernel panic has occurred. The specific content of the panic is as follows: {"bug_type":"210","timestamp":"2026-01-28 14:35:30.00 +0800","os_version":"macOS 13.0 (22A380)","roots_installed":0,"incident_id":"61C9B820-8D1B-4E75-A4EB-10DC2558FA75"} { "build" : "macOS 13.0 (22A380)", "product" : "Macmini9,1", "socId" : "0x00008103", "kernel" : "Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103", "incident" : "61C9B820-8D1B-4E75-A4EB-10DC2558FA75", "crashReporterKey" : "6435F6BD-4138-412A-5142-83DD7E5B4F61", "date" : "2026-01-28 14:35:30.16 +0800", "panicString" : "panic(cpu 0 caller 0xfffffe0026c78c2c): "apciec[pcic0-bridge]::handleInterrupt: Request address is greater than 32 bits linksts=0x99000001 pcielint=0x02220060 linkcdmsts=0x00000000 (ltssm 0x11=L0)\n" @AppleT8103PCIeCPort.cpp:1301\nDebugger message: panic\nMemory ID: 0x6\nOS release type: User\nOS version: 22A380\nKernel version: Darwin Kernel Version 22.1.0: Sun Oct 9 20:14:30 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T8103\nFileset Kernelcache UUID: C222B4132B9708E5E0E2E8B8C5896410\nKernel UUID: 0BFE6A5D-118B-3889-AE2B-D34A0117A062\nBoot session UUID: 61C9B820-8D1B-4E75-A4EB-10DC2558FA75\niBoot version: iBoot-8419.41.10\nsecure boot?: YES\nroots installed: 0\nPaniclog version: 14\nKernelCache slide: 0x000000001d1b4000\nKernelCache base: 0xfffffe00241b8000\nKernel slide: 0x000000001e3f8000\nKernel text base: 0xfffffe00253fc000\nKernel text exec slide: 0x000000001e4e0000\nKernel text exec base: 0xfffffe00254e4000\nmach_absolute_time: 0x907c3082\nEpoch Time: sec usec\n Boot : 0x6979adbb 0x00023a6a\n Sleep : 0x00000000 0x00000000\n Wake : 0x00000000 0x00000000\n Calendar: 0x6979ae1a 0x00064953\n\nZone info:\n Zone map: 0xfffffe1000834000 - 0xfffffe3000834000\n . VM : 0xfffffe1000834000 - 0xfffffe14cd500000\n . RO : 0xfffffe14cd500000 - 0xfffffe1666e98000\n . GEN0 : 0xfffffe1666e98000 - 0xfffffe1b33b64000\n . GEN1 : 0xfffffe1b33b64000 - 0xfffffe2000830000\n . GEN2 : 0xfffffe2000830000 - 0xfffffe24cd4fc000\n . GEN3 : 0xfffffe24cd4fc000 - 0xfffffe299a1c8000\n . DATA : 0xfffffe299a1c8000 - 0xfffffe3000834000\n Metadata: 0xfffffe3f4d1ac000 - 0xfffffe3f551ac000\n Bitmaps : 0xfffffe3f551ac000 - 0xfffffe3f5ac94000\n\nCORE 0 recently retired instr at 0xfffffe002569d7a0\nCORE 1 recently retired instr at 0xfffffe002569eea0\nCORE 2 recently retired instr at 0xfffffe002569eea0\nCORE 3 recently retired instr at 0xfffffe002569eea0\nCORE 4 recently retired instr at 0xfffffe002569eea0\nCORE 5 recently retired instr at 0xfffffe002569eea0\nCORE 6 recently retired instr at 0xfffffe002569eea0\nCORE 7 recently retired instr at 0xfffffe002569eea0\nTPIDRx_ELy = {1: 0xfffffe2000c23010 0: 0x0000000000000000 0ro: 0x0000000000000000 }\nCORE 0 PVH locks held: None\nCORE 1 PVH locks held: None\nCORE 2 PVH locks held: None\nCORE 3 PVH locks held: None\nCORE 4 PVH locks held: None\nCORE 5 PVH locks held: None\nCORE 6 PVH locks held: None\nCORE 7 PVH locks held: None\nCORE 0 is the one that panicked. Check the full backtrace for details.\nCORE 1: PC=0xfffffe00279db94c, LR=0xfffffe00260d5d9c, FP=0xfffffe8ffecaf850\nCORE 2: PC=0xfffffe0025be76b0, LR=0xfffffe0025be7628, FP=0xfffffe8fff08f5f0\nCORE 3: PC=0x00000001c7cacd78, LR=0x00000001c7cacd84, FP=0x000000016f485130\nCORE 4: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffe1dff00\nCORE 5: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff5eff00\nCORE 6: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8ffed8bf00\nCORE 7: PC=0xfffffe002557f55c, LR=0xfffffe002557f55c, FP=0xfffffe8fff11bf00\nCompressor Info: 0% of compressed pages limit (OK) and 0% of segments limit (OK) with 0 swapfiles and OK swap space\nPanicked task 0xfffffe1b33aad678: 0 pages, 470 threads: pid 0: kernel_task\nPanicked thread: 0xfffffe2000c23010, backtrace: 0xfffffe8fff6eb6a0, tid: 265\n\t\t ... Kernel Extensions in backtrace:\n com.apple.driver.AppleT8103PCIeC(1.0)[A595D104-026A-39E5-93AA-4C87CE8C14D2]@0xfffffe0026c619d0->0xfffffe0026c86c97\n dependency: com.apple.driver.AppleARMPlatform(1.0.2)[11A9713E-6739-3A4C-8571-2D8EAA062278]@0xfffffe0025f13ff0->0xfffffe0025f6255f\n dependency: com.apple.driver.AppleEmbeddedPCIE(1)[E71CBCCD-AEB8-3E7B-933D-4FED4241BF13]@0xfffffe002654e0b0->0xfffffe00265684c7\n dependency: com.apple.driver.ApplePIODMA(1)[A419BABC-A7A3-316D-A150-7C2C2D1F6D53]@0xfffffe00269a24b0->0xfffffe00269a6c3b\n dependency: com.apple.driver.IODARTFamily(1)[03997E20-8A3F-3412-A4E8-BD968A75A07D]@0xfffffe00275bcf50->0xfffffe00275d0a3f\n dependency: com.apple.iokit.IOPCIFamily(2.9)[EC78F47B-530B-3F87-854E-0A0A5FD9BBB2]@0xfffffe0027934350->0xfffffe002795f3d3\n dependency: com.apple.iokit.IOReportFamily(47)[843B39D3-146E-3992-B7C7-960148685DC8]@0xfffffe0027963010->0xfffffe0027965ffb\n dependency: com.apple.iokit.IOThunderboltFamily(9.3.3)[B22BC005-BB7B-32A3-99C0-39F3BDBD8E54]@0xfffffe0027a5e3f0->0xfffffe0027b9a1a3\n\nlast started kext at 1915345919: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nlast stopped kext at 1774866338: com.sobb.pcie-dma\t1.0.0d1 (addr 0xfffffe00240e47f0, size 9580)\nloaded It seems that the DMA request address initiated by FPGA exceeded 32 bits, which was intercepted by PCIe root port and resulted in a kernel panic.This is also the case on macOS (M2). I have tried the following code interface: IOBufferMemoryDescriptor: a. withCapacity(bufferSize, kIODirectionInOut, true); b. inTaskWithPhysicalMask(kernel_task, kIODirectionInOut, bufferSize, 0x00000000FFFFFFFFULL)。 The physical addresses of the constructed descriptors are all >32 bits; IODMACommand: a. withSpecification(kIODMACommandOutputHost64, 64, 0, IODMACommand::kMapped, 0, 0),gen64IOVMSegments() The allocated IOVM address must be>32 bits, which will generate a kernel panic when used later. b.withSpecification(kIODMACommandOutputHost32, 32, 0, IODMACommand::kMapped, 0, 0),gen32IOVMSegments() The allocation of IOVM failed with error code kIOReturnenMessageTooLarge. So after the above attempts, the analysis shows that the strategy of Dart+PCIe root port on macOS (Apple Silicon) is causing the failure of 64 bit DMA address transfer. I have two questions: a. Does Dart in macOS (Apple Silicon) definitely not allocate <=32-bit IOVM addresses? b. Is there any other way to achieve DMA transfer for FGPA devices on macOS (Apple Silicon)? Thanks!
Replies
9
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0
Views
624
Activity
Feb ’26
Missing "Dolby Vision Profile" Option in Deliver Page - DaVinci Resolve 20 on iPadOS 26
Dear Support Team, ​I am writing to seek technical assistance regarding a persistent issue with Dolby Vision exporting in DaVinci Resolve 20 on my iPad Pro 12.9-inch (2021, M1 chip) running iPadOS 26.0.1. ​The Issue: Despite correctly configuring the project for a Dolby Vision workflow and successfully completing the dynamic metadata analysis, the "Dolby Vision Profile" dropdown menu (and related embedding options) is completely missing from the Advanced Settings in the Deliver page. ​My Current Configuration & Steps Taken: ​Software Version: DaVinci Resolve Studio 20 (Studio features like Dolby Vision analysis are active and functional). ​Project Settings: Color Science: DaVinci YRGB Color Managed. ​Dolby Vision: Enabled (Version 4.0) with Mastering Display set to 1000 nits. ​Output Color Space: Rec.2100 ST2084. ​Color Page: Dynamic metadata analysis has been performed, and "Trim" controls are functional. ​Export Settings: ​Format: QuickTime / MP4. ​Codec: H.265 (HEVC). ​Encoding Profile: Main 10. ​The Problem: Under "Advanced Settings," there is no option to select a Dolby Vision Profile (e.g., Profile 8.4) or to "Embed Dolby Vision Metadata." ​Potential Variables: ​System Version: I am currently running iPadOS 26. ​Apple ID: My iPad is currently not logged into an Apple ID. I suspect this might be preventing the app from accessing certain system-level AVFoundation frameworks or Dolby DRM/licensing certificates required for metadata embedding. ​Could you please clarify if the "Dolby Vision Profile" option is dependent on a signed-in Apple ID for hardware-level encoding authorization, or if this is a known compatibility issue with the current iPadOS 26 build? ​I look forward to your guidance on how to resolve this. ​Best regards, INSOFT_Fred
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0
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220
Activity
Feb ’26
iOS printing – Finishing (Punch) options not applied for images unless a preset is selected
When printing image/photo files via AirPrint, selected finishing options (e.g., Punch) are not applied unless a preset is chosen. reproduction steps: Select an image on iOS Tap Print → choose printer/server Set Finishing Options → Punch Print Observed: Finishing options not applied IPP trace shows no finisher attributes in the request working scenario: Select any Preset (e.g., Color) before printing Finishing options are then included in IPP and applied Note: Issue does not occur when printing PDFs from iOS; finisher attributes are sent correctly. Is this expected AirPrint behavior for image jobs, or could this be a bug in how iOS constructs the IPP request for photos?
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3
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261
Activity
Mar ’26
macOS 26.4 Beta breaks keyboard remapping for built-in MacBook keyboards – significant ecosystem impact
Since macOS 26.4 Beta 1, virtual HID devices created via DriverKit can no longer intercept key events from the built-in MacBook keyboard. External keyboards still work. This is confirmed and tracked here: https://github.com/pqrs-org/Karabiner-Elements/issues/4402 One possible lead (from LLM-assisted analysis of Apple's open-source IOHIDFamily code and cross-referencing community reports): macOS 26.4 Beta may have introduced or modified a security policy referred to as com.apple.iohid.protectedDeviceAccess, which could block IOHIDDeviceOpen for the Apple Internal Keyboard connected via SPI transport (AppleHIDTransportHIDDevice). This appears related to a "GamePolicy" check in IOHIDDeviceClass.m that gates whether processes can open HID devices. This has not been independently verified and may or may not be the root cause. This has far-reaching consequences. Karabiner-Elements alone has over 21,000 GitHub stars and is used by hundreds of thousands of macOS users for keyboard customization, accessibility workflows, ergonomic setups, and multilingual input. This change completely breaks its core functionality on any MacBook. Beyond Karabiner, this affects every developer building keyboard remapping, input customization, or accessibility tooling via DriverKit virtual HID devices — including commercial applications currently in development. I'd argue that the power and flexibility of keyboard customization on macOS is a genuine competitive advantage for the platform. Developers and power users choose Macs partly because tools like this exist. Restricting this capability would be detrimental to the ecosystem and to Apple's appeal among professional users. I'd like to understand: is this an intentional security change or a regression? If intentional, is there a migration path?
Replies
1
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221
Activity
Mar ’26
Can't get USBSerialDriverKit driver loaded
I am writing a DriverKit driver for the first that uses the USBSerialDriverKit. The driver its purpose is to expose the device as serial interface (/dev/cu.tetra-pei0 or something like this). My problem: I don't see any logs from that driver in the console and I tried like 40 different approaches and checked everything. The last message I see is that the driver get successfully added to the system it is in the list of active and enabled system driver extensions but when I plug the device in none of my logs appear and it doesn't show up in ioreg. So without my driver the target device looks like this: +-o TETRA PEI interface@02120000 <class IOUSBHostDevice, id 0x10000297d, registered, matched, active, busy 0 (13 ms), retain 30> | { | "sessionID" = 268696051410 | "USBSpeed" = 3 | "UsbLinkSpeed" = 480000000 | "idProduct" = 36886 | "iManufacturer" = 1 | "bDeviceClass" = 0 | "IOPowerManagement" = {"PowerOverrideOn"=Yes,"DevicePowerState"=2,"CurrentPowerState"=2,"CapabilityFlags"=32768,"MaxPowerState"=2,"DriverPowerState"=0} | "bcdDevice" = 9238 | "bMaxPacketSize0" = 64 | "iProduct" = 2 | "iSerialNumber" = 0 | "bNumConfigurations" = 1 | "UsbDeviceSignature" = <ad0c16901624000000ff0000> | "USB Product Name" = "TETRA PEI interface" | "locationID" = 34734080 | "bDeviceSubClass" = 0 | "bcdUSB" = 512 | "USB Address" = 6 | "kUSBCurrentConfiguration" = 1 | "IOCFPlugInTypes" = {"9dc7b780-9ec0-11d4-a54f-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | "UsbPowerSinkAllocation" = 500 | "bDeviceProtocol" = 0 | "USBPortType" = 0 | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | "USB Vendor Name" = "Motorola Solutions, Inc." | "Device Speed" = 2 | "idVendor" = 3245 | "kUSBProductString" = "TETRA PEI interface" | "kUSBAddress" = 6 | "kUSBVendorString" = "Motorola Solutions, Inc." | } | +-o AppleUSBHostCompositeDevice <class AppleUSBHostCompositeDevice, id 0x100002982, !registered, !matched, active, busy 0, retain 5> | { | "IOProbeScore" = 50000 | "CFBundleIdentifier" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "IOProviderClass" = "IOUSBHostDevice" | "IOClass" = "AppleUSBHostCompositeDevice" | "IOPersonalityPublisher" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "bDeviceSubClass" = 0 | "CFBundleIdentifierKernel" = "com.apple.driver.usb.AppleUSBHostCompositeDevice" | "IOMatchedAtBoot" = Yes | "IOMatchCategory" = "IODefaultMatchCategory" | "IOPrimaryDriverTerminateOptions" = Yes | "bDeviceClass" = 0 | } | +-o lghub_agent <class AppleUSBHostDeviceUserClient, id 0x100002983, !registered, !matched, active, busy 0, retain 7> | { | "IOUserClientCreator" = "pid 1438, lghub_agent" | "IOUserClientDefaultLocking" = Yes | } | +-o IOUSBHostInterface@0 <class IOUSBHostInterface, id 0x100002986, registered, matched, active, busy 0 (5 ms), retain 9> | | { | | "USBPortType" = 0 | | "IOCFPlugInTypes" = {"2d9786c6-9ef3-11d4-ad51-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | | "USB Vendor Name" = "Motorola Solutions, Inc." | | "bcdDevice" = 9238 | | "USBSpeed" = 3 | | "idProduct" = 36886 | | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | | "bInterfaceSubClass" = 0 | | "bConfigurationValue" = 1 | | "locationID" = 34734080 | | "USB Product Name" = "TETRA PEI interface" | | "bInterfaceProtocol" = 0 | | "iInterface" = 0 | | "bAlternateSetting" = 0 | | "idVendor" = 3245 | | "bInterfaceNumber" = 0 | | "bInterfaceClass" = 255 | | "bNumEndpoints" = 2 | | } | | | +-o lghub_agent <class AppleUSBHostInterfaceUserClient, id 0x100002988, !registered, !matched, active, busy 0, retain 6> | { | "UsbUserClientBufferStatistics" = {"IOMemoryDescriptor"=0,"IOBufferMemoryDescriptor"=0,"IOSubMemoryDescriptor"=0} | "IOUserClientCreator" = "pid 1438, lghub_agent" | "UsbUserClientBufferAllocations" = {"Bytes"=0,"Descriptors"=0} | "IOUserClientDefaultLocking" = Yes | } | +-o IOUSBHostInterface@1 <class IOUSBHostInterface, id 0x100002987, registered, matched, active, busy 0 (5 ms), retain 9> | { | "USBPortType" = 0 | "IOCFPlugInTypes" = {"2d9786c6-9ef3-11d4-ad51-000a27052861"="IOUSBHostFamily.kext/Contents/PlugIns/IOUSBLib.bundle"} | "USB Vendor Name" = "Motorola Solutions, Inc." | "bcdDevice" = 9238 | "USBSpeed" = 3 | "idProduct" = 36886 | "IOServiceDEXTEntitlements" = (("com.apple.developer.driverkit.transport.usb")) | "bInterfaceSubClass" = 0 | "bConfigurationValue" = 1 | "locationID" = 34734080 | "USB Product Name" = "TETRA PEI interface" | "bInterfaceProtocol" = 0 | "iInterface" = 0 | "bAlternateSetting" = 0 | "idVendor" = 3245 | "bInterfaceNumber" = 1 | "bInterfaceClass" = 255 | "bNumEndpoints" = 2 | } | +-o lghub_agent <class AppleUSBHostInterfaceUserClient, id 0x10000298a, !registered, !matched, active, busy 0, retain 6> { "UsbUserClientBufferStatistics" = {"IOMemoryDescriptor"=0,"IOBufferMemoryDescriptor"=0,"IOSubMemoryDescriptor"=0} "IOUserClientCreator" = "pid 1438, lghub_agent" "UsbUserClientBufferAllocations" = {"Bytes"=0,"Descriptors"=0} "IOUserClientDefaultLocking" = Yes } more details in my comment.
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6
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367
Activity
Mar ’26
How to get a IOSerialBSDClient attached?
I have a driver extending IOUserUSBSerial and I want the device to show up as /dev/tty.mycustombasename-123 and /dev/cu. respectively. How can I achieve that?
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1
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321
Activity
Feb ’26
Kernel Panic: Power state transition (0 -> 2) timeout during DriverKit (DEXT) load sequence (IOUserSCSIParallelInterfaceController)
Hi Everyone, We are currently migrating a mature legacy KEXT to DriverKit for our PCIe SCSI storage controller (connected via Thunderbolt 3). During the DEXT load sequence, we have observed that the system automatically triggers a power state transition from State 0 (Off) to State 2 (On). However, this process results in a Kernel Panic due to a timeout after approximately 21 seconds. We have verified that our implementation of Start_Impl, UserInitializeController_Impl, and SetPowerState_Impl executes extremely fast, with a total execution time of less than one second. Specifically, SetPowerState_Impl returns kIOReturnSuccess immediately upon being called. Furthermore, our current Info.plist does not contain any IOPowerManagement dictionary or related keys. Despite the fast execution and the absence of explicit power management declarations in the plist, the kernel power management state machine (IOServicePM) still generates a 21-second timeout, leading to the following panic: Panic Log: panic(cpu 7 caller 0xfffffe0020be8fec): MySCSIDriver::setPowerState(0xfffffe2fb1a65c00 : 0xfffffe0020bfed88, 0 -> 2) timed out after 21257 ms @IOServicePM.cpp:5609 com.example.driver.dext: ( id: com.example.driver.dext; path: /Library/SystemExtensions/[UUID]/com.example.driver.dext; state: loaded ) Note on Previous Discussion: I would like to express my gratitude to Kevin from Apple DTS for the helpful discussion regarding the implementation of BundleParallelTask on the forums. Since then, we have shifted our development focus toward completing the overall management ecosystem, delivering a comprehensive operational interface for users, and handling specific user environments and behaviors. Our current priority is ensuring system stability—specifically resolving these Thunderbolt-related power management issues (sleep/wake)—to prepare the product for upcoming testing. I remain very grateful for the guidance provided on batch task optimization and intend to resume those optimizations once this critical stability baseline is secured. Technical Guidance Needed for PM Migration In our legacy KEXT, we utilized PMinit(), registerPowerDriver(), and joinPMtree() to precisely control the timing of power management registration. In transitioning to the DriverKit SDK, we have not found clear guidance on several key points: Standardized Migration Path: What is the recommended way to implement equivalent power management initialization (formerly PMinit) within a DriverKit subclass? In DriverKit, how should we replicate the behavior of manually calling registerPowerDriver and joinPMtree to ensure the driver is only monitored once the hardware is ready? Implicit Power Registration: Why does the system enforce a setPowerState(0 -> 2) transition on a subclass of IOUserSCSIParallelInterfaceController even when no IOPowerManagement dictionary is defined in the Info.plist? Is this a default behavior of the SCSI or PCI transport framework? Thunderbolt Specifics: Are there specific power proxying requirements or configurations for PCIe devices over Thunderbolt to avoid conflicts with the default IOPCIFamily power policies? Best Regards, Charles
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248
Activity
Mar ’26
DriverKit Entitlement Model Has No Viable Path for Open Source and Community-Maintained Drivers
While I welcome the arrival of a userspace implementation of drivers, DriverKit as it stands has some notable flaws. My main concern is the ability of open-source projects like HoRNDIS being able to access paid developer accounts and the limited entitlement scope (plus the waiting period) for what is essentially a hobbyist free project. Even if the developer is a professional company, some legacy hardware will go unsupported because of a lack of support from the vendor. Providing a way for users who need access to older hardware would be needed. Three concrete requests: A class-level or wildcard VID/PID entitlement for open source projects with a verifiable public repository A free or reduced-cost entitlement path for non-commercial volunteer-maintained drivers Published approval criteria and timelines so projects can plan accordingly Depreciating kexts without providing an accessible successor for community projects isn't security, it is gatekeeping access to hardware that is critically needed. Is this use case on the roadmap at all? Developers deserve a clear answer.
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184
Activity
Mar ’26
DriverKit vs MFi for iPad custom hardware serial communication?
I have a custom hardware board that I want to communicate serially with from an iPad. Should I use the DriverKit route or the MFi route?
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243
Activity
Mar ’26
iOS AirPrint sends print-quality=high when file-type is photo even if user selects “normal”
Hi everyone, I observed a behavior with AirPrint from an iPhone and wanted to confirm if this is expected behavior from iOS. Scenario tested: File type: Photo Print-quality selected by the user: Normal Observation (from packet capture): When checking the PCAP for the request sent from the iPhone, the print-quality attribute is always sent as high, even though the user selected Normal in the UI. Question: Is this an expected behavior in iOS/AirPrint where photos are always sent with print-quality=high regardless of the user-selected print quality? Or could this be a bug?
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145
Activity
Mar ’26
DriverKit vs MFi for iPad custom hardware serial communication?
I have a custom hardware board that I want to communicate serially with from an iPad. Should I use the DriverKit route or the MFi route?
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198
Activity
Mar ’26
Why don't my os_log entries show up until the second time my driver loads?
I'm in the process of writing a DriverKit USBHostInterface driver, and while I'm finally starting to get there, I've run into a bit of a frustration with logging. Naturally I have a liberal amount of os_log calls that I'm using to troubleshoot my driver. However I've noticed that they don't show up until after the first time my driver has loaded. Meaning, for example, suppose I make a new build of my driver and it's bundled user-mode app, install the bundle to /Applications, run the installer, verify it took with systemextensionsctl list, fire up Console and start streaming log entries, then plug in my device. I can see the log entries that show that my driver is loaded, etc., then a bunch of kernel -> log entries, but none of my Start method log entries. If I unplug my device and plug it in again, my log entries show up as expected. Why is this and, more importantly, how can I fix it? I'd like to see those log entries the first time the driver loads, if I could.
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204
Activity
Mar ’26
Supported way to expose an iPhone+controller as a macOS gamepad without restricted entitlements?
I’m prototyping a personal-use system that lets an iPhone with a physically attached controller act as an input device for a Mac. End goal: Use the iPhone as the transport and sensor host Use the attached physical controller for buttons/sticks Map the iPhone gyroscope to the controller’s right stick to get gyro aim in Mac games / cloud-streamed games such as GeForce NOW that don't support the gyro. What I’m trying to understand is whether Apple supports any path for this on macOS that does NOT require restricted entitlements or paid-program-only capabilities. What I’ve already found: CoreHID virtual HID device creation appears to require com.apple.developer.hid.virtual.device HIDDriverKit / system extensions appear to require Apple-granted entitlements as well GCVirtualController does not seem to solve the problem because I need a controller-visible device that other apps can see, not just controls inside my own app So my concrete question is: Is there any supported, entitlement-free way for a personal macOS app to expose a game-controller-like input device that other apps can consume system-wide? If not, is the official answer that this class of solution necessarily requires one of: CoreHID with restricted entitlement HIDDriverKit/system extension entitlement some other Apple-approved framework or program I’m missing I’m not asking about App Store distribution. This is primarily for local/personal use during development. I’m trying to understand the supported platform boundary before investing further. Any guidance on the recommended architecture for this use case would be appreciated.
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215
Activity
Mar ’26
Dual Monitor Studio Display XDR fails on MacBook Pro M4 Pro
I have two Macbook Pros: 14" M4 Pro (company) 16" M4 Max (personal) I work remote full-time and recently purchased 2 of the new Studio Display XDRs. Everything works perfectly however I chose to connect them to the M4 Max. I have a caldigit Element TB5 hub and can daisy chain both monitors through that perfectly. With that said, no matter how I plug them into the M4 Pro I can only ever get one to light up at a time. What I have tried to resolve it: Plug them in individually to the m4 pro Plug them in one at a time, force them to 60hz and then plug them both in. Daisy Chaining the displays Daisy Chaining the displays through the TB5 Hub Nothing works. Only one display comes on and its whichever is plugged in first. I have even tried lowering the refresh to as low as it goes on both manually then plugging them back in. Still nothing. From what I am reading it appears to be that the M4 Pro has 3 display lanes and when I plug the first studio display XDR it is using 2 lanes. If I go down to 60hz which is what the original studio display was, then it should theoretically go down to 1 display lane allowing a second to be plugged in. A bunch of people had the older studio display running 2x 5k ASD monitors on the M4 Pro. Now with the latest Studio Display XDR I am stuck. I was researching possibly editing the EDID of each to mimic the older studio display, but I don't know how to do that easily without BetterDisplay and right now I have no ability to install that. There is a chance I can get approval to run commands / BetterDisplay to get this working if a solution can be found. What I think the ultimate fix is for the firmware / macOS to realize the limitation, force the studio display XDR to 60hz when a second monitor is plugged in and they both would work. A single Studio Display XDR could run 120hz, but immediately upon plugging a second one it swaps to 60hz. I am completely fine with that scenario. I have found a few discussions about this topic with the main one being on apple discussions: https://discussions.apple.com/thread/256262701?sortBy=rank&answerId=261888577022 Someone sort of gave me this idea on Mac because they were trying to use the studio display XDR on windows and it appears to have worked with cloning an older ASD EDID on the new model: https://www.reddit.com/r/mac/comments/1s3ani5/got_studio_display_xdr_working_on_windows_pc_5k/ I don't really know what else to do. I opened a ticket with support. Case # 102853480566, but it went no where. I got disconnected during the first call after describing everything and when they reached back out they didn't even give me 2 seconds to pick up and they hung up and closed the ticket. I really don't want to return the displays because they are beautiful and work beautifully on the m4 max. They should work with 60hz on the m4 pro. Who / How / When can we get this resolved? I would be happy to work with an Apple dev / engineer to help resolve this.
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158
Activity
Mar ’26
iPhone 16 Pro Max — 180s SpringBoard freeze + reboot, started iOS 26.4 Beta 3, persists on stable 26.4
iPhone16PM Clean DFU, no restore, no tweaks. Started on iOS 26.4.3 and still happening on iOS 26.4. Triggers: ∙ Editing Home Screen widgets ∙ Heavy media in Safari ∙ ProMotion UI transitions Panic log — 0x8badf00d watchdog timeout: userspace watchdog timeout: no successful checkins from SpringBoard in 180 seconds. service: backboardd Drivers: com.apple.driver.AppleAVD + com.apple.iokit.IOSurface Is there a solution for this? Thank you.
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152
Activity
Apr ’26
Does using HIDVirtualDevice rule out Mac App Store distribution?
Hi, I’m looking for clarification from folks familiar with CoreHID rather than App Review, as the guys there have not responded to my post (https://developer.apple.com/forums/thread/820676) We have a sandboxed macOS app that creates a virtual HID device (HIDVirtualDevice) as described in Creating virtual devices https://developer.apple.com/documentation/corehid/creatingvirtualdevices To work at all, the app requires the entitlement: com.apple.developer.hid.virtual.device With this entitlement present, macOS shows the system prompt requesting Accessibility permission App would like to control this computer using accessibility features. Grant access to this application in Security and Privacy preferences located in System Preferences. when HIDVirtualDevice(properties:) is called. There is no mention of Accessibility in the HIDVirtualDevice documentation, but the behavior is reproducible and seems unavoidable. My question is therefore: Is creating a virtual HID device from userspace via HIDVirtualDevice considered inherently incompatible with Mac App Store distribution? In other words: Is the Accessibility prompt an expected side‑effect of this API? And if so, does that mean using HIDVirtualDevice is only practical for direct (non–App Store) distribution unless the app is explicitly an accessibility tool? I’m not asking about review policy details—just whether, from a technical/system point of view, HIDVirtualDevice is actually intended to be usable by App Store apps. For context, there seem to be public, non‑accessibility uses of Apple’s virtual HID infrastructure, like this recent post: https://developer.apple.com/forums/thread/820708 and corresponding Github repo this project. I don't know if these intend to use the App Store, but they might end up in the same situation. Any insights from people who’ve worked with CoreHID would be greatly appreciated. Thanks, Magnus
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2w
I requested "DirverKit UserClient Access" Entitlement, But I Distribute App failed.
I requested "DirverKit UserClient Access" Entitlement, But I Distribute App failed. I don't know the reason. I think when I request "DirverKit UserClient Access" I make a mistake. I fill in two Bundle ids in the "Request a System Extension or DriverKit Entitlement" form's "UserClient Bundle IDs" item. The reason is when I Add "DirverKit UserClient Access" Capability in the project of Xcode. The .entitlements file is like this: <string>com.turing.TuringTouch com.turing.TuringTouch.TouchDriver</string> But in "Signing" of Xcode's "Bundle Identifier" can fill in only on "Identifier" therefore they do not match. So I can't Distribute App. I reapply "DirverKit UserClient Access" Entitlement. But decline. The result is "decline". Please help me. Please tell me, how should can I do now? Thank you very much.
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142
Activity
2w
Driverkit driver hangs on macOS
Hello, I have crated a DriverKit driver for macOS and iPad M-series if I ever get the mac driver working. I have the correct entittlements, and matching provisioning profile downloaded manually. The driver loads (no errors!), and is visible in ioreg below the usb device (when plugged). The issue is that I never get any log from the driver, have reduced to minimal working code (below). When I debug with lldb, I load the symbols for my driver and break on init and Start - but lldb never triggers == never calls start or init. This is also why no logs. When I unplug the device, the driver process (ps aux) keeps running, causes a hard crash of the Mac with dext remove/or kill driver.dext process. I have asked Claude - but its just running in circles: check Info.plist=ok, check entitlements=ok, check code (minimal)=ok, check iig=ok, check provisioning profile=ok, check build settings=ok, check ioreg=ok, check code signature=ok, start over I don't get any log from my driver, which is consistent with init() not being called. All logs from kernel & friends (AMFI) do show the driver loading - no errors. Any tips appreciated! // USBDriver.iig #ifndef USBDriver_h #define USBDriver_h #include <USBDriverKit/IOUSBHostInterface.iig> class USBDriver: public IOService { public: virtual bool init() override; virtual void free() override; virtual kern_return_t Start(IOService * provider) override; virtual kern_return_t Stop(IOService * provider) override; }; // USBDriver.cpp #include <os/log.h> #include <DriverKit/DriverKit.h> #include "USBDriver.h" bool USBDriver::init() { if (!super::init()) return false; os_log(OS_LOG_DEFAULT, "terminal.driver: init()"); return true; } kern_return_t IMPL(USBDriver, Start) { os_log(OS_LOG_DEFAULT, "terminal.driver: Start()"); kern_return_t ret = super::Start(provider); if (ret != kIOReturnSuccess) { os_log(OS_LOG_DEFAULT, "terminal.driver: super::Start failed: 0x%08x", ret); return ret; } os_log(OS_LOG_DEFAULT, "terminal.driver: Start() success"); return super::Start(provider); } kern_return_t IMPL(USBDriver, Stop) { os_log(OS_LOG_DEFAULT, "terminal.driver: Stop()"); return super::Stop(provider); } void USBDriver::free() { os_log(OS_LOG_DEFAULT, "terminal.driver: free()"); super::free(); }
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Activity
2w
HID Device Access / Mode Switch
I might be trying to achieve the impossible here, but if there's another way to go about it any advice would be appreciated. I've got an older Linux application that reflashes firmware on a connected USB HID device that I'm trying to port to macOS. Essentially the device starts as an HID interface (0x03/0x01/0x01) but to update firmware receives a simple control payload and then restarts and connects as a different (non-HID) device. However I can't open the HID device at all, I'm guessing this is some sort of permission error (SIP?). AppleUSBHostUserClient::openGated: failed to open IOUSBHostDevice... provider is already opened for exclusive access by AppleUSB20Hub hid_open_path: failed to open IOHIDDevice from mach entry: (0xE00002E2) not permitted AppleUSBXHCICommandRing::setAddress: completed with result code 4 AppleUSBHostPort::createDevice: failed to create device (0xe00002bc) AppleUSBIORequest ... transaction error ... 0xe00002ed Is there any way at all to do this on macOS? Interestingly if you run a Windows VM in VMWare or similar and connect the device to that VM it works, so there's obviously some way but I'd like to create a simple standalone tool.
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194
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2w
macOS Preview appears to hold MTP devices open indefinitely
I am developing a USB MTP device for use with macOS. When the device is connected while Preview is running, I observe the host send OpenSession, then GetDeviceInfo, and then no further MTP commands. I do not see a later CloseSession. Problem is that once this happens, exclusive access to the USB interface is retained, so another application cannot connect to the device. From the device side, there is no obvious way to recover except forcing a USB disconnect/reset or shutting down the USB interface. My questions are: Is this expected behavior for Preview, or for a Preview-related macOS helper? Is it expected on macOS that a client may open an MTP session and then leave it idle without sending CloseSession? I am mainly trying to understand whether this is expected macOS behavior, or whether this should be considered a bug.
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1w